* `light.configure_shadow` has been added. It can either use a camera frustum or
calculate the bounds for a static shadow that doesn't need to be updated every
frame.
* `Light` and `newLight` have `use_shadow`, however it's not used automatically
at the moment. Instead you should call `configure_shadow`.
* Added `updateShadowStorage` which at the moment has to be called manually
after using `configure_shadow`.
* All shadows now share a single texture array per scene, so they can be
accessed by index in the shader and take less shader locations and draw calls.
* Shadow map resolution is also global per scene.
* Add `set_texture_shadow` and `unset_texture_shadow` to configure a texture as
shadow sampler.
* Bias has been removed as an option, it's calculated automatically instead.
* Bias now moves along the normal of the mesh instead of towards the light,
allowing very small biases.
